The controversial killing of teenager Trayvon Martin by neighborhood watch member George Zimmerman has become a national flashpoint for discussions of race and violence. Technology has now entered into the narrative, after an expert in biometric voice analysis said the screams on the 911 most likely did not belong to Zimmerman.

The test was conducted by Tom Owen, of Owen Forensic Services LLC and chair emeritus for the American Board of Recorded Evidence, who was contacted by the Orlando Sentinel. Owen used a software called Easy Voice Biometrics to compare Zimmerman’s voice to the 911 call screams. “I’ve run it against 300 voices and it was better than 99 percent in all cases,” Owen told MSNBC.

When Owen ran Zimmerman’s voice against the scream on the 911 call he got a 48 percent match. He would have expected a more than 90 percent match if the voice was Zimmerman’s, as the audio on the call is quite good. Owen said he couldn’t compare the screams to Trayvon Martin’s voice, as he did not have an audio sample of the teenager.